Bolt-anchor.



` n @Ma 4' H. W. PLEISTER.

BOLT ANCHOR. APPLicATIoN FILED sEPT.18. |917.

\ lli-9.

www #Q27 (W MM@ Patented May 28,1918.

HENRY w. rrinisrna, or wns'iriniin, Naw massi?, assioNon To HENRY B.NEWHALL.

BOLT-ANCHOR.

To all whom t may concern: i

Be it known that I, HENRY W. PLnis'rna, a citizen of the United States,residing at Westfield, in the county ofUnion and"State of New Jersey,have invented certain new and useful Improvements in Bolt-Anchors, ofwhich the following is a. specilication, taken in connection with theaccompanying drawings.

This application is a division of my copending application, Ser. No.121,105, filed Sept. 20, 1916. i

My invention relates to bolt anchorsand more particularly to a boltanchor which has a great holding capacity and yet one which willnotcrack a wall, a partition, a

block of marble, stone or any other material in which it may be desiredto use myboltanchor.

The common form of bolt anchors are exn panded by having the expandingmember, the screw or bolt, move down an inclined surface which extendsapproximately from one end to the other, reaching its nearest approachto the axis of the anchor at the end which is farthestA embedded` in`the wall, block or other material. This causes the maximum expansion tobe at the very end of the bolt anchor. This makesit inipossi ble to usethe ordinary common form of expansion bolt in many locations.

My expansion bolt removes the point of maximum expansion` from the end`of the bolt and insures a gradually lessening grip and wedging actionfrom that point to the end of the bolt.

My present invention relates more particularly to that class of boltanchors known as anchors, or ductile anchors, or lead anchors, or screwanchors, in which the material of the anchor is some relatively softmetal, such as lead or an alloy, in which the screw cuts its owncoperating screwthreads.

My invention further relates to certain details of construction whichwill be described in the specification and pointed out in the claims.

T have shown in the accompanying drawings several illustrativeembodiments of my invention but of course it is to be understood that myinvention is not to be confined simply to the forms illustrated. Inthese drawings the same reference numerals refer to similar parts.

Figure 1 is a longitudinal vertical. section Specicatioiiof 'LettersPatent.

of my bolt anchor shown as a ductile anchor, lead anchor, or screwanchor.

retain-eti iuay es, irais., 1

l Original application led September 20, 1916, Serial No. 121,105.Divided and this application led September Serial No. 191,920. v

Fig. 2 is a vertical section of my anchor mounted in a con'iparativelyshallow block of marble, stone or similar material. The work supportedis shown in section and the wood screw in side elevation.

Fig. 3 is a longitudinal vertical section of` my anchor tion'. i

Fig. 1- is a longitudinal vertical sectiony of the anchor shown in Fig.3 showingit expanded and cooperating with the support to hold the work.

Tnfthe illustrative embodiments of my invention lis an anchor having acollar 2 and two tines 3 and iland an axial bore 5 which has a taperedportion 6 which reaches its nearest approach tothe axis of the anchor at7, and then recedes or flares from that point to-the end 8 of the anchorforming a flaring surface 9. Ordinarily these anchors, or ductileanchors, or lead anchors or screw anchors 1 as they are called in thetrade, are used for lighter work The expanding member is usually a woodlscrew 10 which cuts its own cooperating screwthreads in the anchor as itis screwed home. `llt is well known that in thin walls, or thinpartitions, or thin slabs of stone, mar` provided with a weakeningporble, slate or similar material 11, the ordinary form of lead anchoroften cannot be used for the reason that the maximum ex.

pansioii would occur at, the points 12,12

which will cause thexsurface 13 of the slab` of marble, stone, slate,the partition or other -support 11 to become cracked, chippedor niarringor breaking of the slab `of marble,

stone, slate or wall or other support 11 by removing the maximum strainand wedging stresses from the points 12, 12 to a point rcinovcd from theend 8 of the anchor and far enough away from the surface 13 so as tobring the point of maximum expansion well within the body of the slab ofmarble, stone, slate or wall or partition 11.

In the operation of my invention, Fig. 2, the hole 14 is formed leavinga comparatively thin portion 15. The ductile anchor 1 is then insertedand the work 16 will' be snugly held to the face 17 of the slab ofstone, marble, slate or the partition or other than are lag shields.I

support 11 by means of the wood screw 10 which will cut its owncoperating screwvthreads yin the body of the anchor as it is screwedalong the axial inclinedbore G, the maximum expansion being exertedsubstantially at the points 18, 18, well within the slab of marble,stone, slate or Wall, partition or other support and removed from thethin portion 16. From the points 18, 18, Fig. 2, to the end 8 lof theanchor the gripping action will gradually 'lessen so that at i the veryend 8 ofthe anchor no strains will be'exerted which will cause afracture, crumi bling, orv marring of the face 13 of the support 1-*1whatever material it may be formed yof.

To make the action even more delicate viously, described.

When the wood screw 10, eut-ting its threads .in the body of the anchor19, passes the `point 25 which is the point of minimum diameter of theaxial bore 24, the weakened portions 20, 20 will permit'the end portions28, 28to move slightly with relation to the other portions of the anchorand tend to vcause the'two sides of the valleys 29, 29 to move apart oropen, Fig. 4, should by any circumstances anyconsiderable strain heexerted upon the portions 28. 28 Awhich might have a tendency tocrack orinjure the surface'13. These valleys 29 are preferably formed bycasting` them Within the anchor.

In all figures-of thefdrawings the inclined v and fiaringsurfaees, aswell as the gripping Copies of this patent may be obtained for action ofthe anchor, are somewhatexaggerated for purposes of clearerillustration. Itis also apparent that different thieknesses of work 16can be held by thesame y anchor without the Wood screw 10 binding beforeit has snugly secured the work to the face 17 of the slab of marble,stone, slate or wall or support 1-1.

Having thus described this invention in connection with illustrativeembodiments thereof to the details of which I do not desire to belimited, except as required by the scope of the appended claims, what isclaimed as new and what is desired to secure by Letters Patent is setforth in the appended claims.

What I claim as my invention and desire tol secure by Letters Patentis 1. The combination of a ductile anchor provided with an axial bore ofminimum diameter between its ends said bore flaring from 'its minimumdiameter toward each end, and a screw to directly engage both of saidflaring surfaces to cut its own female threads to expand the ductileanchor.

2. The combination of a ductile anchor provided with an axial bore ofminimum diameter between its ends, said bore 'il-.wing from its minimumdiameter toward each end, said ductile anchor being` provided with oneor more weakenng portions and a screw to directly engage both of saidflaring surfaces to cut its own female threads to expand the ductileanchor.

3. rFhe combination of a ductile anchor having a collar, tines, and anaxial bore having itsminimum diameter between the ends of the anchor andHaring from its mini mum diameter toward each end, and a screw todirectly engage both of said flaring surfaces to cut its own `screwthreads land ex pand the ductile anchor.

4. The combination in a ductile anchor of a collar, tines, an axiallbore having its minimum diameter 'between the ends of the anchor andflaring from its minimum diameter-towardfeach end, said anchor beingprovided 'with yone or more weakeningl portions adjacent'tol'itheminimum diameter of (he axial bore. f

` n HENRY W. PLEISTER. y Witnesses:

MARY R. RYAN,

ELIZABETH J. ROTH.

five 'cents each, by addressing the Commissioner of fPatents,Washington, I).l C.

